Repair to floating point enumerations?
Isaac Dupree
isaacdupree at charter.net
Thu Oct 16 17:31:50 EDT 2008
Christopher Lane Hinson wrote:
>
> I agree with David, we should be using multiplication, not addition.
> However, I think that under the law of least surprise, we should
> require that for all a,b,z:
>
> all (\x -> x >= a && x < z || x <= a && x > z) [a,b..z].
so that [0,0.1..0.3] doesn't include the terminating value
that's a little more than the literal 0.3?
> For example, anything in the neighborhood of this is just unfair, even
> if it's within David's fudge factor:
>
> Prelude> map (\x -> 1 / (x-0.6)) [0,0.1..0.55]
> [-1.6666666666666667,-2.0,-2.5,-3.333333333333334,-5.000000000000001,-10.000000000000002,Infinity]
but that's a significant fudge, 0.5 versus 0.55 versus 0.6
-- right?
-Isaac
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